In European Patent Application EP-A-0 033 094, imidazo-[1,2-a]pyridines are described which carry an aryl substituent in the 8-position, which is preferably a phenyl radical, thienyl radical, pyridyl radical or a phenyl radical substituted by chlorine, fluorine, methyl, tert-butyl, trifluoromethyl, methoxy or cyano. Particularly interesting aryl radicals mentioned in EP-A-0 033 094 are the radicals phenyl, o- or p-fluorophenyl, p-chlorophenyl and 2,4,6-trimethylphenyl, of which the radicals phenyl, o- or p-fluorophenyl and 2,4,6-trimethylphenyl are particularly preferred.--In European Patent Applications EP-A-0 204 285, EP-A-0 228 006, EP-A-0 268 989 and EP-A-0 308 917, imidazo[1,2-a]pyridines are described which carry an unsaturated aliphatic radical, in particular a (substituted) alkynyl radical, in the 3-position.--In European Patent Application EP-A-0 266 890, imidazo[1,2-a]pyridines are described which are substituted in the 8-position by an alkenyl, alkyl or cycloalkylalkyl radical.